﻿#region License

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#endregion

using System;
using System.Text;
using System.Text.Json;

namespace Gremlin.Net.Driver
{
    internal class JsonMessageSerializer
    {
        private readonly string _mimeType;
        private static readonly JsonSerializerOptions JsonDeserializingOptions = new JsonSerializerOptions
            {PropertyNamingPolicy = JsonNamingPolicy.CamelCase};

        public JsonMessageSerializer(string mimeType)
        {
            _mimeType = mimeType;
        }

        public byte[] SerializeMessage(string msg)
        {
            return Encoding.UTF8.GetBytes(MessageWithHeader(msg));
        }

        private string MessageWithHeader(string messageContent)
        {
            return $"{(char) _mimeType.Length}{_mimeType}{messageContent}";
        }

        public TMessage DeserializeMessage<TMessage>(byte[] message)
        {
            if (message == null) throw new ArgumentNullException(nameof(message));
            if (message.Length == 0) return default;
            var reader = new Utf8JsonReader(message);
            var deserialized = JsonSerializer.Deserialize<TMessage>(ref reader, JsonDeserializingOptions);
            return deserialized;
        }
    }
}